Units 3 & 4

Question 1

Gregor Mendel

Answer 1

crossing pea plants, pure breeding to examine differences. Discovered dominant and recessive traits, disproved blended inheritance. Principles of segregation and independent assortment

Question 2

Thomas H. Morgan

Answer 2

observed crossover during meiosis concluded that “genes” are on chromosomes. He proposed the “beads on a string “ model. (explains how traits are passed on to the next generation)

Question 3

Kary Mullis

Answer 3

Polymerase Chain Reaction (PCR), 1993 Nobel Prize

Question 4

Hershey & Chase

Answer 4

DNA is the hereditary material, 1969 Nobel Prize

Question 5

Oswald Avery

Answer 5

DNA is the transforming principle

Question 6

Francis Crick

Answer 6

• recognized that although the DNA molecule had only four “letters,” it must code for the 20 amino acids that made up proteins. Concluded that the code for an amino acid must contain three bases, or triplets (codons)
• The Central Dogma

Question 7

James Watson

Answer 7

DNA structure (double helix), 1962 Nobel Prize (along with Francis Crick)

Question 8

Frederick Sanger

Answer 8

Human mitochondrion sequenced

Question 9

True-breeding

Answer 9

a term used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate

Question 10

Dominant

Answer 10

An allele that is always expressed

Question 11

Meiosis

Answer 11

Cell division that produces reproductive cells in sexually reproducing organisms

Question 12

Gamete

Answer 12

Sex cell

Question 13

Dihybrid cross

Answer 13

A cross between two individuals, concentrating on two definable traits

Question 14

Chromosome

Answer 14

A threadlike, gene-carrying structure is found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins

Question 15

Somatic cell

Answer 15

any cell of a living organism other than the reproductive cells (body cells)

Question 16

Replication

Answer 16

Copying process by which a cell duplicates its DNA

Question 17

The cell cycle

Answer 17

The regular sequence of growth and division that cells undergo

Question 18

Genome

Answer 18

all of an organism’s genetic material

Question 19

Codon

Answer 19

A specific sequence of three bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid

Question 20

rRNA

Answer 20

ribosomal RNA; type of RNA that makes up part of the ribosome

Question 21

Sister chromatid

Answer 21

a structure that contains identical DNA copies and is formed during DNA replication

Question 22

Mutation

Answer 22

change in a DNA sequence that affects genetic information

Question 23

Recessive

Answer 23

An allele that is masked when a dominant allele is present

Question 24

Allele

Answer 24

Different forms of a gene

Question 25

Zygote

Answer 25

fertilized egg

Question 26

Regulatory gene

Answer 26

A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes

Question 27

Synapsis

Answer 27

the pairing of homologous chromosomes during meiosis

Question 28

Eukaryote

Answer 28

A cell that contains a nucleus and membrane-bound organelles

Question 29

Gene

Answer 29

A segment of DNA on a chromosome that codes for a specific trait

Question 30

Sex cell

Answer 30

An egg or sperm cell (gamete); a sex cell carries half the number of chromosomes found in other body cells

Question 31

Diploid

Answer 31

two complete sets of chromosomes, one from each parent

Question 32

Central Dogma

Answer 32

a theory that states that, in cells, information only flows from DNA to RNA (transcription) to proteins (translation)

Question 33

Ribosome

Answer 33

Cytoplasmic organelles at which proteins are synthesized

Question 34

Chromatin

Answer 34

A substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

Question 35

Mendelian trait

Answer 35

a trait completely determined by a single gene

Question 36

F1 generation

Answer 36

the first generation of offspring obtained from an experimental cross of two organisms

Question 37

Genotype

Answer 37

the genetic makeup of an organism

Question 38

Homozygous

Answer 38

Having two identical alleles for a particular gene/trait

Question 39

Mitosis

Answer 39

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Question 40

Translation

Answer 40

The process by which mRNA is decoded and a protein is produced

Question 41

Autosome

Answer 41

Any chromosome that is not a sex chromosome

Question 42

Reduction division

Answer 42

another name for meiosis I, the division where homologous pairs separate

Question 43

Sex chromosome

Answer 43

one of two chromosomes that determines an individual's sex

Question 44

Haploid

Answer 44

An organism or cell having only one complete set of chromosomes

Question 45

mRNA

Answer 45

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

Question 46

Amino acid

Answer 46

Building blocks of protein

Question 47

DNA base

Answer 47

Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

Question 48

Blending inheritance

Answer 48

n outdated, incorrect theory that the phenotype of an offspring is a blend of the parent's phenotypes

Question 49

F2 generation

Answer 49

Offspring resulting from the interbreeding of the hybrid F1 generation

Question 50

Phenotype

Answer 50

An organism's physical appearance, or visible traits

Question 51

Heterozygous

Answer 51

An organism that has two different alleles for a trait

Question 52

Universal genetic code

Answer 52

refers to the fact that particular codons specify the same amino acids in almost all organisms

Question 53

Transcription

Answer 53

the process whereby the DNA sequence in a gene is copied into mRNA

Question 54

Complementary base pairing

Answer 54

- In DNA, T pairs with A and G pairs with C; | - In RNA, U pairs with A and G pairs with C

Question 55

Crossing over/Recombination

Answer 55

when homologous chromosomes trade parts of chromosome arms

Question 56

Homologous

Answer 56

the term used to refer to chromosomes that each has a corresponding chromosome from the opposite-sex parent

Question 57

Tetrad

Answer 57

structure containing 4 chromatids that form during meiosis

Question 58

tRNA

Answer 58

transfer RNA; type of RNA that carries amino acids to the ribosome

Question 59

Cytoplasm

Answer 59

A jellylike fluid inside the cell in which the organelles are housed

Question 60

Homologous chromosomes

Answer 60

Chromosomes that have the same sequence of genes and the same structure